When manufacturing integrated circuit devices, one or more photomasks or reticles may be used. Generally a photomask may be an opaque plate with transparencies that allow light to shine through a defined pattern. The patterns in the photomask may define the patterns found in an integrated circuit device. If there are defects in the pattern, the integrated circuit device may not function properly. In order to find defects that may occur during the manufacturing process, it may be important to focus the inspection tool so that the image generated is accurate enough to allow for detection of defects.